My experience with setting up the GOG Anniversary Edition with a bunch of sex mods was that, generally, Anniversary Edition is catered for just like Special Edition. I did manage to get every mod I wanted running (albeit with some headaches, especially Schlongs of Skyrim). I think the main concern is mods that haven't been updated for 1.6, and for those cases you'll need an older version of Special Edition and older versions of all the other mods. But I didn't find it necessary for the mods I wanted.
tl;dr if you don't care about the AE content, there's no reason to get it, but the compatibility is about the same or slightly better on SE.